The present invention has for its objects salts of keto acids and of amine derivatives, as well as their use for the preparation of pharmaceutical compositions for the treatment of pathologies in which are involved silent neurons.
The nociceptive message results from the intense activation of the free terminals (nociceptors) of the C and Axcex4 fibers which under physiological conditions take part in the regulation of the function of the organs. These fibers are contained in the cutaneous, muscular and articular tissues as well as in the walls of the viscera.
In the digestive tract as well as in the bladder and the biliary ducts, this nerve structure cohabits with a population of silent neurons (Mayer, E. A.; Gebhart, G. F.; Gastroenterology, 1994, 107, 271-293) whose expression appears only in the presence of an inflammatory or nervous lesion.
This physiopathological mechanism inspired the creation of the model of distension of the colon first irritated with 1% acetic acid, in rat. This model is hence representative of the illnesses of digestive origin and is used particularly for detecting compounds active in the treatment of the irritable intestine syndrome (IIS). IIS is characterized by the presence of abdominal pain. Patients having this pathology have a lowered threshold of digestive sensitivity.
Morphine is active on the model of colic distension whilst the classical analgesics (AINS, aspirin, paracetamol) are inactive in the test. They are on the other hand active in the xe2x80x9cwrithing testxe2x80x9d (model of visceral pain in which the silent neurons are not involved) which is effected by intraperitoneal injection of phenylbenzoquinone or 3% acetic acid in rat or a mouse. Morphine is hence capable of modifying the reactivity of the silent nociceptors, which AINS cannot do.
Similarly, one opinion, described in JP 43-05524 as an analgesic, is active in the xe2x80x9cwrithing testxe2x80x9d at 500 and 1000 mg/kg by intravenous route in mice. It is also active in a somatic pain test in which the silent neurons are not involved (Kawabata, Atsugumi et coll., Eur. J. Pharmacol., 1996, 296 (1), 23-31), at doses between 300 and 1000 mg/kg by subcutaneous route in rat.
By contrast, it is inactive in the model of colic distension in rat at doses of 1 to 20 mg/kg by oral route (Table I). Ornithine is thus not capable of modifying the reactivity of the silent nociceptors at these dosages.
Moreover, J. Goldhill et coll. (Gastroenterology, April 1996, 110 (4), abstract A916) have shown that glutamine is active in the test of colic distension at a dose of 6 mg/kg by rectal route in rat (local administration on the irritated colic mucosa).
Finally, xcex1-ketoglutarate of di-ornithine is used in therapy (French patent 3 533 M) to improve the proteic metabolism of starved subjects. It is also known as a hormonal stimulant (growth hormone and insulin) and stimulating cellular growth.
The present invention follows from the discovery by the inventors, of the fact that salts of the general formula (I):
(X)n1,Y,(Z)n2xe2x80x83xe2x80x83(I)
in which:
X is an amino acid;
Y is a keto acid;
Z is an amino acid or a polyamine,
n1 and n2 represent 0 or 1, provided that when n1=0 then n2=1, and when n2=0, n1=1,
have the property of increasing the threshold of perception of digestive pain and as a result are capable of modifying the reactivity of the silent nociceptors in an amount at least 1 mg/kg by oral route.
This discovery is the more unexpected, because the keto acids separately tested are inactive. The separately tested amino acids are also inactive or active at higher dosages (see Table I hereafter).
The activity of these salts is not due to the keto acid alone or to the amino acid alone, but to the synergy between these two types of compounds.
Thus, by way of illustration, Table I shows nicely that:
the comparisons 1 and 2 are inactive whilst the compounds of Examples 1 and 2 (salts between comparisons 1 and 2) are active at 1 mg/kg;
comparison 3 is inactive whilst the compound of Example 6 (salt between comparisons 3 and 2) is also active from 1 mg/kg;
comparison 4 is active at 10 mg/kg whilst the compound of Example 5 (salt between comparisons 1, 2 and 4) is active from 1 mg/kg;
comparison 5 is active only from 20 mg/kg whilst the compounds of Examples 3 (salts of comparisons 1 and 5) and 4 (salts of comparisons 1, 2 and 5) are active from 10 mg/kg.
The present invention has for its object the use of compounds of the following general formula (I):
(X)n1,Y,(Z)n2xe2x80x83xe2x80x83(I)
in which:
n1 and n2 are 0 or 1, provided that when n1=0 then n2=1, and when n2=0 then n1=1,
X is a natural amino acid, provided that when n20 then X is a basic amino acid such as:
ornithine,
arginine,
lysine,
or, histidine,
Y is a keto acid of the following formula (II):
Rxe2x80x94COxe2x80x94COOHxe2x80x83xe2x80x83(II)
xe2x80x83in which R is an alkyl or alcanolic acid group, substituted or not, from about 1 to about 10 carbon atoms, particularly a keto acid of formula (II) in which when R is:
xe2x80x94CH3, said keto acid is pyruvic acid,
xe2x80x94CH2xe2x80x94CH3, said keto acid is xcex1-ketobutyric acid,
xe2x80x94CH(CH3)2, said keto acid is xcex1-ketoisovaleric acid,
xe2x80x94CH(CH3)xe2x80x94CH2xe2x80x94CH3, said keto acid is xcex2-methylvaleric xcex1-keto acid,
xe2x80x94CH2xe2x80x94CH(CH3)2, said keto acid is xcex1-keto isocaprilic acid,
xe2x80x94(CH2)2xe2x80x94COOH, said keto acid is xcex1-keto glutaric acid,
xe2x80x94(CH2) 3xe2x80x94COOH, said keto acid is xcex1-keto adipic acid,
Z represents:
a natural amino acid, particularly an amino acid selected from ornithine, arginine, lysine, histidine or glutamine,
or, a polyamine comprising at least two primary, secondary or tertiary amine functions, spaced by a linear or branched hydrocarbon chain of about 3 to 10 carbon atoms, particularly a polyamine of the following formula (III):
R1xe2x80x94HNxe2x80x94(CH2)n-NHxe2x80x94R2xe2x80x83xe2x80x83(III)
xe2x80x83in which:
n represents a whole number comprised between 4 and 5, and
when n=4,
R1 and R2 are H,
or, R1 is H and R2 is (CH2)3NH2,
or, R1 and R2 are (CH2)3NH2,
when n=5,
R1 and R2 are H, 
or, R1 is H and R2 is a group of the formula particularly a polyamine selected from cadaverine, putrescine, spermidine, spermine or agmatine,
for the preparation of a medication adapted for the treatment of human or animal pathologies in which are involved the silent neurons, such as pathologies of the digestive tract, of the bladder and of the biliary ducts.
Of course, the compounds of formula (I) above result from the formation of principally ionic bonds, and in no case of covalent bonds, between the different constituents X, Y or Z. As a result, the order of appearance of the different constituents in formula (I) has no particular significance, and this formula (I) should be understood to comprehend also the compounds of the formula (X)n1, Y, (Z)n2 those of formula (Z)n2, Y, (X)n1; (X)n1, (Z)n2, Y; (Z)n2, (X)n1, Y; Y, (X)n1, (Z)n2; Y, (Z)n2, (X)n1.
Preferably, the invention has for its object the above-mentioned use of compounds of formula (I) as defined above, in which Y is a keto acid selected from xcex1-ketoglutaric acid, or xcex1-ketobutyric acid.
The invention has more particularly for its object the above-mentioned use, of compounds of formula (I) in which:
n1=1, and n2=0 or 1,
X is an amino acid selected from ornithine, arginine or glutamine,
Y is a keto acid selected from xcex1-ketoglutaric acid, or xcex1-ketobutyric acid,
and, when n2=1, Z is:
a natural amino acid, particularly ornithine, arginine or glutamine,
or a polyamine of the above formula (III) such as cadaverine, putrescine, spermidine, spermine or agmatine.
Compounds of formula (I) in which n1=1, and n2=0, particularly preferred for their use in the field of the present invention, are those in which:
X is ornithine and Y is xcex1-ketoglutaric acid, namely mono-ornithine xcex1-ketoglutarate,
X is ornithine and Y is xcex1-ketobutyric acid, namely mono-ornithine xcex1-ketobutyrate,
or those in which:
X is arginine and Y is xcex1-ketobutyric acid, namely arginine xcex1-ketobutyrate,
X is lysine and Y is xcex1-ketobutyric acid, namely lysine xcex1-ketobutyrate,
X is histidine and Y is xcex1-ketobutyric acid, namely histidine xcex1-ketobutyrate,
X is arginine and Y is xcex1-ketoisocaproate acid, namely arginine xcex1-ketoisocaproate,
X is ornithine and Y is xcex1-ketoisocaproate acid, namely ornithine xcex1-ketoisocaproate,
X is ornithine and Y is xcex1-keto-xcex2 methylvalerate acid, namely ornithine xcex1-keto-xcex2 methylvalerate,
X is arginine and Y is xcex1-keto-xcex2 methylvalerate acid, namely arginine xcex1-keto-xcex2 methylvalerate,
X is arginine and Y is xcex1-keto-isovaleric acid, namely arginine xcex1-keto-isovalerate,
X is ornithine and Y is xcex1-keto-isovaleric acid, namely ornithine xcex1-keto-isovalerate.
Compounds of the formula (I) in which n1=1, and n2=1, particularly preferred for their use in the field of the present invention, are those in which:
X is ornithine, Y is xcex1-keto-glutaric acid, and Z is ornithine, namely diornithine xcex1-keto-glutarate,
X is arginine, Y is xcex1-keto-glutaric acid, and Z is arginine, namely diarginine xcex1-keto-glutarate,
X is ornithine, Y is xcex1-keto-glutaric acid, and Z is arginine, namely ornithine and arginine xcex1-keto-glutarate,
X is ornithine, Y is xcex1-keto-glutaric acid, and Z is glutamine, namely ornithine and glutamine xcex1-keto-glutarate,
X is ornithine, Y is xcex1-keto-glutaric acid, and Z is spermidine, namely ornithine and spermidine xcex1-keto-glutarate.
Preferably, the compound used in the present invention is di-ornithine xcex1-keto-glutarate.
The invention has more particularly for its object the above-mentioned use, of compounds of the formula (I) in which:
n1=0 or 1, and n2=1,
when n1=1, X is a natural amino acid, such as ornithine, arginine or glutamine,
Y is a keto acid selected from xcex1-keto-glutaric acid, or xcex1-keto-butyric acid,
Z is a polyamine of the above formula (III) such as cadaverine, putrescine, spermidine, spermine or agmatine.
A compound of formula (I) in which n1=0, and n2=1, particularly preferred for its use in the field of the present invention, is that in which Y is xcex1-keto-glutaric acid and Z is spermidine, namely spermidine xcex1-keto-glutarate.
The invention also has for its object compounds of the following general formula (IV):
(X)na, (Y)nb, Zxe2x80x83xe2x80x83(IV)
in which:
na and nb are 0 or 1, provided that when na=0 then nb=1 and when nb=0 then na=1,
X is a natural amino acid, particularly a basic amino acid such as ornithine, arginine, lysine or histidine,
Y is a keto acid of the above formula (II),
Z is a polyamine comprising at least two primary, secondary or tertiary amine functions, spaced by a linear or branched hydrocarbon chain of about 3 to 10 carbon atoms, particularly a polyamine of the above formula (III), such as cadaverine, putrescine, spermidine, spermine or agmatine.
The invention more particularly has for its object the compound of general formula (IV) in which na=0 and nb=1, Y is xcex1-keto-glutaric acid and Z is spermidine, and corresponding to the compound of formula (I) in which n1=0 and n2=1, Y is xcex1-keto-glutaric acid and Z is spermidine, namely spermidine xcex1-keto-glutarate.
Preferably, the compounds as described above are present in the form of salts between two constituents X and Y, or Y and Z, or between the three constituents X, Y and Z.
The weight proportion of the various constituents is preferably comprised between 0.8 and 1.2, such that the sum of the proportions of each of the constituents is equal to 2 in the case of a salt between two constituents X and Y, or Y and Z, or is equal to 3 in a salt between three constituents X, Y and Z.
Preferably, the above-mentioned proportion of the different constituents is comprised between 0.9 and 1.1.
Particularly preferred compounds are those in which the different constituents X and Y, or Y and Z, or X, Y and Z, are in equimolar ratio, which is to say that each of the constituents is in a weight proportion of 1, such that the sum of the proportions of each of the constituents is equal to 2 in a salt of two constituents X and Y, or Y and Z, or is equal to 3 in a salt of the three constituents X, Y and Z.
The invention has more particularly for its object compounds selected from the group consisting of arginine xcex1-keto-butyrate, lysine xcex1-keto-butyrate, histidine xcex1-keto-butyrate, arginine xcex1-keto-isocaproate, ornithine xcex1-keto-isocaproate, ornithine xcex1-keto-xcex2 methylvalerate, arginine xcex1-keto-xcex2 methylvalerate, arginine xcex1-keto-isovalerate, and ornithine xcex1-keto-isovalerate.
The invention also has for its object any pharmaceutical composition comprising, as its active principle, a compound of formula (I) described above, in association with a pharmaceutically acceptable vehicle.
The invention also concerns any pharmaceutical composition comprising, as its active principle, a polyamine of the above-described formula (III), and more particularly cadaverine, putrescine, spermidine, spermine or agmatine, or a compound of the above formula (IV), in association with a pharmaceutically acceptable vehicle.
The pharmaceutical compositions according to the invention are present in a form administrable by oral, parenteral, or rectal route.
Preferably, the pharmaceutical compositions according to the invention are characterized in that the dosage for the active principle is about 0.1 to 50 mg/kg/day, preferably 1 to 20 mg/kg/day by oral and rectal routes, and about 1 xcexcg/kg/day to 10 mg/kg/day by parenteral route.
Preferred pharmaceutical compositions according to the invention are present in the form administrable by oral route, in a unit dosage of 1 mg to 5 g of active principle per dose and preferably 10 mg to 1 g taken in 1 to 4 doses per day. Compositions also preferred according to the invention are present in the form administrable by parenteral route in a unit dose of 50 xcexcg to 500 mg of active principle taken as 1 to 2 injections per day.
The invention has more particularly for its object the use of one or several compounds of formula (I) described above for the preparation of a medication designed for the treatment of human or animal pathologies, in which are involved the silent neurons and more particularly for the symptomatic treatment of pain associated with these pathologies.
The invention also has for its object the use of polyamines of the above-described formula (III) and more particularly of cadaverine, putrescine, spermidine, spermine or agmatine, or the use of compounds of the above formula (IV) for the preparation of a medication adapted for the treatment of the pathologies mentioned above.
Among the above-mentioned human or animal pathologies in which the silent neurons are involved, adapted to be treated by the present invention, can be cited principally the pathologies of the digestive tract, of the bladder and of the biliary ducts, and more particularly the pain associated with these pathologies, of which particularly the pains:
in the trouble of transit and intestinal discomfort associated with intestinal functional troubles (dyspepsia, irritable intestine syndrome, irritable colon . . . )
in the biliary ducts
in the rectocolic hemorrhage
in the Crohn malady
in the gastric or duodenal ulcer
in chronic gastritis
in colorectal or gastric cancer
in gastroenteritis and intestinal flu
connected with an intestinal or colic pseudo-obstruction
in radical ileitis
digestive or visceral post-operative pain
in diarrhea, spasms, constipation, megacolon, megarectum
in spasms of the bladder
in vesical paresis.
The compounds according to the invention can be prepared by dissolving the various constituents in basic form in water. The salt thus obtained in solution in water is then precipitated by means of a solvent miscible with water such as alcohol (methanol, ethanol, isopropanol) or by acetone or acetonitrile, then collected by filtration. The aqueous solution can also be lyophilized.
The solvent obtained in any case can be purified by mixing with a solvent such as diethyl ether or acetonitrile.